This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-319545, filed Nov. 10, 1999, the entire contents of which are incorporated herein by reference.
The present invention relates to a data communication method and a data communication system. More particularly, this invention relates to a data communication method and a data communication system for data communication between a probing apparatus and a tester.
In a semiconductor device fabrication process, a great number of IC chips T are formed on a surface of a wafer W, as shown in FIG. 3. On the basis of results of tests of electrical characteristics of chips T on the wafer W, the chips T are screened and classified into good ones and defective ones. The tests are carried out using a probing apparatus, for example, as shown in FIG. 4. In FIG. 4, a tester 20 is connected to a probing apparatus 10 over a communication line 30. In the probing apparatus 10, chips T on a wafer W are electrically connected to the tester 20, and the tester 20 tests various electrical characteristics of the chips T.
The probing apparatus 10, as shown in FIG. 4, comprises a loading chamber 11 for feeding and prealigning a wafer W, and a probing chamber 12 for receiving the wafer W from the loading chamber 11 and testing electrical characteristics thereof. Within the probing chamber 12, there are provided a mainchuck 13 for supporting the wafer W, an aligning mechanism 14 for aligning the wafer W at a predetermined position, and a probe card 15. The probe card 15 has a plurality of probes 15A which are to be put in electrical contact with test electrodes of the chips T on the wafer W. The mainchuck 13 supporting the aligned wafer W is index-fed within the probing chamber 12. The electrical characteristics of each chip T are measured in every index-feed operation in each chip or in units of several chips. A test head 21 is disposed on a head plate 16 of the probing chamber 12. The test head 21 is electrically connected to the probe card 15.
Data communication is performed between the probing apparatus 10 (more specifically the test head 21) and the tester 20. For example, the probing apparatus 10 transmits to the tester 20 a measurement data signal indicative of the kind of a test for the wafer W placed on the mainchuck 13 (e.g. coordinates of positions of chips T on wafer W, the order of measurement, channel information on the number of chips to be tested at a time, the number of defective chips within a hatched region in FIG. 3 (i.e. the number of chips requiring no test) (hereinafter referred to as xe2x80x9con-wafer informationxe2x80x9d) as well as a measurement start signal. After measuring the electrical characteristics of each chip T, the tester 20 transmits measurement result data along with a measurement end signal to the probing apparatus 10.
As is shown in FIG. 4, the test head 21 and tester 20 are connected via GP-IB interface terminals and a cable (hereinafter referred to as xe2x80x9cGP-IB linexe2x80x9d) 30 which are adopted in ordinary measuring devices. The aforementioned data such as on-wafer information, channel information and measurement result information is transmitted between the test head 21 and tester 20 over the GP-IB line 30. In some cases, the probing apparatus 10 and tester 20 are connected via, e.g. a TTL interface and a cable (hereinafter referred to as xe2x80x9cTTL linexe2x80x9d).
With an increase in diameter of the wafer W and in integration density of chips T, the through-put has decreased more and more. Under the circumstances, it is very important to increase the speed of tests. The GP-IB line, which is currently used for general purposes, is advantageous in that a great deal of data can be transmitted at a time. However, it requires much time for communication, and high-speed communication cannot be achieved. Thus, the increase in through-put is limited. Specifically, each time the mainchuck supporting the wafer is shifted in an index-feeding manner, a measurement signal and a measurement start signal are transmitted between the probing apparatus 10 and tester 20. In addition, after the measurement is finished, measurement result data and a measurement end signal are transmitted between the probing apparatus 10 and tester 20. Where the transmission is effected over the GP-IB line 30, a time of 0.2 to 0.3 second, for instance, is needed to transmit the measurement signal and measurement result data between the tester 20 and probing apparatus 10 each time the wafer mainchuck is shifted in the indexfeeding manner. Because of this time, the through-put cannot be enhanced. On the other hand, the TTL line is suitable for high-speed data communication, but the amount of data to be transmitted is small (e.g. the data amount corresponding to 8 chips). Thus, the data for more than 8 chips cannot be transmitted.
The present invention aims at solving the above problems and transmitting a great deal of data, such as all measurement data and measurement result data relating to an object to be tested, in a batch at high speed.
The object of the present invention is to provide a data communication method and a data communication system capable of enhancing a through-put.
According to an aspect of the present invention, there is provided a data communication method for data communication in a probing apparatus connected to a tester and measuring electrical characteristics of a plurality of objects to be tested, comprising the steps of:
transmitting, in a batch, measurement data necessary for measurement of the electrical characteristics of the objects from the probing apparatus to the tester, prior to conducting a test of the electrical characteristics of the objects; and
transmitting, in a batch, measurement result data on two or more of the objects from the tester to the probing apparatus after the electrical characteristics of the two or more of the objects have been measured.
In this data communication method, it is preferable that the measurement data and the measurement result data are transmitted over an Ethernet.
In these data communication method, it is preferable that before and after the electrical characteristics of the two or more of the objects are measured, a predetermined signal is transmitted between the tester and the probing apparatus over at least one of a TTL interface line and a GP-IB line.
In these data communication method, it is preferable that a measurement start signal is transmitted from the probing apparatus to the tester over the TTL interface line before the electrical characteristics of the two or more of the objects are measured, and a measurement end signal is transmitted from the tester to the probing apparatus over the TTL interface line after the electrical characteristics of the two or more of the objects are measured.
According to another aspect of the invention, there is provided a data communication system between a probing apparatus and a tester, the data communication system comprising a network for transmitting, in a batch, measurement data necessary for measurement of electrical characteristics of a plurality of objects to be tested from the probing apparatus to the tester, and for transmitting, in a batch, measurement result data on the plurality of the objects from the tester to the probing apparatus.
In this data communication system, it is preferable that the network is an Ethernet.
It is preferable that these data communication system further comprise at least one of a TTL interface line and a GP-IB line over which a predetermined signal is transmitted between the tester and the probing apparatus before and after the electrical characteristics of the two or more of the objects are measured.
It is preferable that these data communication system further comprise a TTL interface line over which a measurement start signal is transmitted from the probing apparatus to the tester before the electrical characteristics of the two or more of the plurality of the objects are measured, and over which a measurement end signal is transmitted from the tester to the probing apparatus after the electrical characteristics of the two or more of the objects are measured.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.